The present invention relates to a substrate treating apparatus for treating semiconductor wafers and the like and a substrate treating method using the treating apparatus.
A semiconductor device, such as an IC or LSI, is manufactured in processes including a designing process for designing an integrated circuit to be formed on a semiconductor substrate, a mask forming process for delineating electron beams and the like that are used to form the integrated circuit, and a wafer manufacturing process for forming a semiconductor wafer of a given thickness from a single-crystal ingot. The manufacturing processes further include wafer treating processes for forming the integrated circuit or semiconductor device on the semiconductor wafer, an assembly process for dividing the semiconductor wafer into semiconductor substrates and packaging each substrate to form a semiconductor device, an inspection process. The wafer treating processes include a thin film forming process, oxidation process, doping process, resist treatment process, exposure process, etching process, cleaning process, etc. A dedicated manufacturing device is provided for each wafer treating process. The semiconductor manufacturing devices further include an exhaust gas processing device, which is an essential device for environmental health.
A plurality of chemical fluids may be mixed as they are used in some conventional substrate cleaning devices. As shown in FIG. 5, chemical fluids 1 and 2 are introduced into a mixing tank 10 through nozzles, individually, and mixed into a fluid mixture 3 in the tank. The fluid mixture 3 in the tank 10 is guided onto a to-be-treated substrate (semiconductor wafer) 5 through a pipe. The mixture 3 is discharged through a nozzle 6, which is connected to the pipe, to clean the surface of the semiconductor wafer 5. After the wafer surface is thus cleaned with the chemical fluids, it is washed by pure water 4 discharged from a nozzle 7. Thereafter, the semiconductor wafer is dried. As shown in FIG. 6, two or more nozzles may be located close to the semiconductor wafer 5 so that chemical fluids 1 and 2 can be discharged through their corresponding nozzles to be mixed on the semiconductor wafer 5. In either of the systems shown in FIGS. 5 and 6, the chemical fluid treatment and water washing operation are carried out in an open-to-atmosphere system or in a chamber that is large enough to hold the semiconductor wafer, nozzles, etc. therein.
According to the conventional system shown in FIG. 5, the fluid mixture is prepared in advance, so that chemical fluids that can be decomposed by mixing, such as a fluid mixture of HCl and H2O2, mixture of NH4OH and H2O2, etc., may change their compositions with time as their active H2O2 is decomposed by reaction even while the semiconductor wafer is not being treated. According to the conventional system shown in FIG. 6, on the other hand, the chemical fluids decompose and change less with time. If the two or more nozzles discharge the chemical fluids in different positions, however, the fluids cannot be mixed uniformly enough over the semiconductor substrate.
According to either of the techniques shown in FIGS. 5 and 6, the chemical fluids produce mists in the fluid treatment in the open-to-atmosphere system or in the chamber that is large enough to hold the wafer, nozzles, etc. therein. In the case of the fluid mixture of NH4OH and H2O2 or HCl and H2O2, ammonia, hydrochloric acid, or other highly volatile components may volatilize during the wafer treatment, so that the chemical fluid composition in the discharge region is different from that in the outer peripheral portion of the semiconductor wafer that is distant from the discharge region. Further, NH3 or HCl gas may be discharged into the environment, thereby arousing a problem of environmental pollution. In another case, O2, CO2, and other impurities in the atmosphere may penetrate into the pure water during the water washing operation, thus exerting a bad influence on the semiconductor wafer.
The present invention has been contrived in consideration of these circumstances, and its object is to provide a semiconductor manufacturing apparatus for treating a semiconductor wafer in sheet form, in which chemical fluids can spread uniformly over the semiconductor wafer without substantially decomposing and changing their compositions, so that production of mists or volatilization of the chemical fluids over the surface of the semiconductor wafer can be restrained, and a substrate treating method using the manufacturing apparatus.
According to the present invention, there is provided a substrate treating apparatus that is used in an etching process, cleaning process, etc. for wafer treatment, out of manufacturing processes a semiconductor device. This treating apparatus has a multi-nozzle structure, such as a double-nozzle structure, including an outer tube nozzle, through which at least a chemical fluid or a combination of a chemical fluid and a gas is discharged onto a semiconductor wafer, and an inner tube nozzle, through which at least a chemical fluid or a combination of a chemical fluid and a gas can be discharged into the outer tube nozzle. The wafer top of the outer tube has a structure that extends parallel to the semiconductor wafer, and is adapted to be not contact with the semiconductor wafer as the chemical fluid or gas is discharged from a region near a discharge port during treatment.
The chemical fluids are discharged simultaneously through the multi-nozzle so that they can be efficiently mixed near the semiconductor wafer, and the outer tube nozzle is provided with a cover plate (hereinafter referred to as a wafer top) that serves as a top plate for the semiconductor wafer. Thus, the chemical fluids can be restrained from producing mists or volatilizing. Moreover, since the outer tube nozzle has the wafer top, the area of contact between pure water and the atmosphere is. so small that impurities in the atmosphere can be restrained from penetrating into the pure water during water washing operation. If N2 is discharged from the outer tube nozzle or the inner tube nozzle therein in a drying process, furthermore, introduction of the atmosphere is limited, so that production of watermarks, which requires oxygen, can be also restrained.
A substrate treating apparatus according to a first aspect of the present invention comprises an outer tube nozzle through which a chemical fluid, a combination of a chemical fluid and a gas, pure water, or a combination of pure water and a gas is discharged onto a substrate to be treated; and an inner tube nozzle through which a chemical fluid, a combination of a chemical fluid and a gas, pure water, or a combination of pure water and a gas is discharged onto the to-be-treated substrate, the inner tube nozzle being provided in the outer tube nozzle in such a manner that the inner tube nozzle and the outer tube nozzle constitute a multi-nozzle structure, wherein the outer tube nozzle has at a distal end thereof a wafer top for the to-be-treated substrate, the wafer top extending parallel to the to-be-treated substrate from the distal end and being adapted to be not in contact with the to-be-treated substrate during treatment.
In the substrate treating apparatus according to the first aspect of the present invention, the inner tube nozzle may be located so that it is coaxial with the outer tube nozzle.
In the substrate treating apparatus according to the first aspect of the present invention, the to-be-treated substrate supporting stage may be located under the multi-nozzle so as to face the same and be rotatable in a manner such that its center of rotation is coincident with the center of the multi-nozzle. A moving up/down apparatus for moving up/down the supporting stage may be provided so to adjust a distance between the to-be-treated substrate and the wafer top of the outer tube nozzle during treatment.
In the substrate treating apparatus according to the first aspect of the present invention, a space defined between the to-be-treated substrate and the wafer top of the outer tube nozzle may be filled up with the chemical fluid while the chemical fluid is being discharged.
In the substrate treating apparatus according to the first aspect of the present invention, a diameter of the wafer top of the outer tube nozzle may be twice as large as an outside diameter of the outer tube nozzle or larger and is 20% or more of a diameter of the-to-be-treated substrate. Since the effect of the wafer treatment varies depending on the capacity of a treatment chamber, the diameter of the wafer top of the outer tube nozzle should preferably be twice as large as an outside diameter of the outer tube nozzle or larger and be 20% or more of a diameter of the to-be-treated substrate. Since the function and effect of the present invention are remarkable if the top structure is sized in this manner, the area of the to-be-treated substrate should be set correspondingly.
A substrate treating method according to a second aspect of the present invention comprises a process for opposing an outer tube nozzle through which a chemical fluid, a combination of a chemical fluid and a gas, pure water, or a combination of pure water and a gas is discharged and an inner tube nozzle provided in the outer tube nozzle through which inner tube nozzle a chemical fluid, a combination of a chemical fluid and a gas, pure water, or a combination of pure water and a gas is discharged, to a substrate to be treated, the inner tube nozzle and the outer tube nozzle constituting a substrate treating apparatus with a multi-nozzle structure, a process for discharging the chemical fluid or the combination of the chemical fluid and the gas through the nozzles to clean the to-be-treated substrate with the resulting mixture; and a process for washing the to-be-treated substrate cleaned with the resulting fluids, by pure water discharged through at least one of the inner tube nozzle and the outer tube nozzle.
In the substrate treating method according to the second aspect of the present invention, the method may further comprises a process for drying the to-be-treated substrate washed by pure water. The gas may be discharged through at least one of the inner tube nozzle and the outer tube nozzle during the drying process lest the atmosphere be able to be introduced into the gap between the to-be-treated substrate and the substrate treating apparatus.
In the substrate treating method according to the second aspect of the present invention, the gas may be discharged through at least one of the inner tube nozzle and the outer tube nozzle during the drying process is nitrogen.
In the substrate treating method according to the second aspect of the present invention, the substrate treating apparatus may be set in a treatment chamber having a nitrogen atmosphere therein.
If N2 is discharged through the outer tube nozzle during the drying process, the atmosphere cannot penetrate through the gap between the semiconductor wafer and the wafer top, so that an N2 atmosphere can be formed over the wafer surface. Thus, production of watermarks that is attributable to the presence of oxygen in the atmosphere can be restrained.
In the case where the semiconductor wafer is rotated by means of a rotating chuck as the fluid mixture is discharged through the coaxial multi-nozzle, the chemical fluids can be spread more uniformly over the semiconductor wafer if the respective discharge centers of the outer and inner tube nozzles are on the center of rotation of the semiconductor substrate. The optimum value of the distance between the wafer top and the semiconductor wafer changes depending on the delivery of the chemical fluids or pure water and the delivery of N2. By freely adjusting this distance, therefore, production of mists or volatilization of the fluids can be restrained most effectively. During the water washing operation, moreover, the pure water is never touched by the atmosphere, so that impurities in the atmosphere can be fully prevented from penetrating into the pure water.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.